hom_mat2d_scaleT_hom_mat2d_scaleHomMat2dScaleHomMat2dScalehom_mat2d_scale (算子)

名称

hom_mat2d_scaleT_hom_mat2d_scaleHomMat2dScaleHomMat2dScalehom_mat2d_scale — 为齐次二维变换矩阵添加缩放。

签名

描述

hom_mat2d_scalehom_mat2d_scaleHomMat2dScaleHomMat2dScaleHomMat2dScalehom_mat2d_scale adds a scaling by the scale factors SxSxSxSxsxsx and SySySySysysy to the homogeneous 2D transformation matrix HomMat2DHomMat2DHomMat2DHomMat2DhomMat2Dhom_mat_2d and returns the resulting matrix in HomMat2DScaleHomMat2DScaleHomMat2DScaleHomMat2DScalehomMat2DScalehom_mat_2dscale. The scaling is described by a 2×2 scaling matrix S. It is performed relative to the global (i.e., fixed) coordinate system; this corresponds to the following chain of transformation matrices:

The point (PxPxPxPxpxpx,PyPyPyPypypy) is the fixed point of the transformation, i.e., this point remains unchanged when transformed using HomMat2DScaleHomMat2DScaleHomMat2DScaleHomMat2DScalehomMat2DScalehom_mat_2dscale. To obtain this behavior, first a translation is added to the input transformation matrix that moves the fixed point onto the origin of the global coordinate system. Then, the scaling is added, and finally a translation that moves the fixed point back to its original position. This corresponds to the following chain of transformations:

To perform the transformation in the local coordinate system, i.e., the one described by HomMat2DHomMat2DHomMat2DHomMat2DhomMat2Dhom_mat_2d, use hom_mat2d_scale_localhom_mat2d_scale_localHomMat2dScaleLocalHomMat2dScaleLocalHomMat2dScaleLocalhom_mat2d_scale_local。

注意

It should be noted that homogeneous transformation matrices refer to a general right-handed mathematical coordinate system. If a homogeneous transformation matrix is used to transform images, regions, XLD contours, or any other data that has been extracted from images, the row coordinates of the transformation must be passed in the x coordinates, while the column coordinates must be passed in the y coordinates. Consequently, the order of passing row and column coordinates follows the usual order (RowRowRowRowrowrow,ColumnColumnColumnColumncolumncolumn). This convention is essential to obtain a right-handed coordinate system for the transformation of iconic data, and consequently to ensure in particular that rotations are performed in the correct mathematical direction.

Note that homogeneous matrices are stored row-by-row as a tuple; the last row is usually not stored because it is identical for all homogeneous matrices that describe an affine transformation. For example, the homogeneous matrix is stored as the tuple [ra, rb, tc, rd, re, tf]. However, it is also possible to process full 3×3 matrices, which represent a projective 2D transformation.

执行信息

• 多线程类型：可重入（与非独占算子并行运行）。
• 多线程作用域：全局（可从任何线程调用）。
• 未采用并行化处理。

参数

结果

hom_mat2d_scalehom_mat2d_scaleHomMat2dScaleHomMat2dScaleHomMat2dScalehom_mat2d_scale returns 2 ( H_MSG_TRUE) if both scale factors are not 0。如有必要，则抛出异常。

可能的前趋

hom_mat2d_identityhom_mat2d_identityHomMat2dIdentityHomMat2dIdentityHomMat2dIdentityhom_mat2d_identity, hom_mat2d_translatehom_mat2d_translateHomMat2dTranslateHomMat2dTranslateHomMat2dTranslatehom_mat2d_translate, hom_mat2d_scalehom_mat2d_scaleHomMat2dScaleHomMat2dScaleHomMat2dScalehom_mat2d_scale, hom_mat2d_rotatehom_mat2d_rotateHomMat2dRotateHomMat2dRotateHomMat2dRotatehom_mat2d_rotate, hom_mat2d_slanthom_mat2d_slantHomMat2dSlantHomMat2dSlantHomMat2dSlanthom_mat2d_slant, hom_mat2d_reflecthom_mat2d_reflectHomMat2dReflectHomMat2dReflectHomMat2dReflecthom_mat2d_reflect

可能的后继

hom_mat2d_translatehom_mat2d_translateHomMat2dTranslateHomMat2dTranslateHomMat2dTranslatehom_mat2d_translate, hom_mat2d_scalehom_mat2d_scaleHomMat2dScaleHomMat2dScaleHomMat2dScalehom_mat2d_scale, hom_mat2d_rotatehom_mat2d_rotateHomMat2dRotateHomMat2dRotateHomMat2dRotatehom_mat2d_rotate, hom_mat2d_slanthom_mat2d_slantHomMat2dSlantHomMat2dSlantHomMat2dSlanthom_mat2d_slant, hom_mat2d_reflecthom_mat2d_reflectHomMat2dReflectHomMat2dReflectHomMat2dReflecthom_mat2d_reflect

另见

hom_mat2d_scale_localhom_mat2d_scale_localHomMat2dScaleLocalHomMat2dScaleLocalHomMat2dScaleLocalhom_mat2d_scale_local

模块

基础

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